Description

Cryptosporidiosis is a parasitic infection caused by Cryptosporidium hominis, Cryptosporidium parvum and occasionally other species of Cryptosporidium (1,2). It is transmitted by ingestion of fecally contaminated food or water, including water swallowed while swimming; by exposure to fecally contaminated environmental surfaces; and by the fecal-oral route from person to person (e.g., while changing diapers, caring for an infected person, or engaging in certain sexual behaviors) (1,2).

Occurrence

Cryptosporidiosis is a common cause of childhood diarrhea, especially in developing countries, while sporadic cryptosporidiosis transmission occurs worldwide (1,2). Cryptosporidiosis outbreaks have been reported from North America, Europe, Latin America, Australia, and Asia. Outbreaks have been traced to recreational water exposure, drinking water, contact with animals (especially calves), contaminated food, hospitals, and day-care settings (3).

Risk for Travelers

For travelers to developing countries, risk of infection is highest for those with the greatest exposure to potentially contaminated food or water (4).

Clinical Presentation

Symptoms include watery diarrhea, abdominal cramps, vomiting, and fever. In immune competent persons, symptoms last an average of 6-10 days but can last up to several weeks (5,6). In persons with severely weakened immune systems, such as those with AIDS, cryptosporidiosis can become chronic and can be fatal (1,2).

Prevention

No vaccine is available. To avoid contracting cryptosporidiosis, travelers should be advised to follow the precautions described in the Risks from Food and Drink section in Chapter 2 (3). Cryptosporidiosis is poorly inactivated by chlorine or iodine disinfection. Water can be treated effectively by boiling or filtration with an absolute 1-micron filter. Specific information on preventing cryptosporidiosis through filtration can be found in “Preventing Cryptosporidiosis: A Guide to Water Filters and Bottled Water” at http://www.cdc.gov/ncidod/dpd/parasites/cryptosporidiosis/factsht_crypto_prevent_water.htm.

Treatment

The Food and Drug Administration has approved nitaxozanide suspension (Alinia, Romark Laboratories) for treatment of cryptosporidiosis and giardiasis in children and nitaxozanide tablets for treatment of giardiasis in adults (7,8). Nitazoxanide tablets are a potentially useful treatment for immunocompetent adults with cryptosporidiosis.

References

1. Guerrant RL. Cryptosporidiosis: an emerging, highly infectious threat. Emerg Infect Dis. 1997;3:51-7.
2. Kosek M, Alcantara C, Lima AA, Guerrant RL. Cryptosporidiosis: an update. Lancet Infect Dis. 2001;1:2629.
3. Hlavsa MC, Watson JC, Beach MJ. Cryptosporidiosis surveillance—United States 1999-2002. MMWR Surveill Summ. 2005 Jan 28;54(1):1-8.
4. Roy SL, DeLong SM, Stenzel SA, Shiferaw B, Roberts JM, Khalakdina A, et al. Risk factors for sporadic cryptosporidiosis among immunocompetent persons in the United States from 1999 to 2001. J Clin Microbiol. 2004;42:2944-51.
5. Taylor DN, Connor BA, Shlim DR. Chronic diarrhea in the returned traveler. Med Clin North Am. 1999;83:1033-52.
6. Thielman NM, Guerrant RL. Persistent diarrhea in the returned traveler. Infect Dis Clin North Am. 1998;12:489-501.
7. Nitazoxanide (Alinia)—a new anti-protozoal agent. Med Lett Drugs Ther. 2003;45:29-31.
8. Bailey JM, Erramouspe J. Nitazoxanide treatment for giardiasis and cryptosporidiosis in children. Ann Pharmacother. 2004;38:634-40.